See [[passMedicine Summaries#Evaluation of gradual visual loss]]

[!TIP] Mnemonic: RIFC: retina - ipsi, Field - contra

• A particular side of the retina is innervated by the same side of the brain.

• This means that a side of the visual field is connected to the contralateral side of the brain

See also:

• [[opticRadiation1.jpeg]]
• [[opticRadiation3.jpg]]

[!INFO] Retrochiasmal lesions will cause contralateral homonymous visual field defects.
According to the figure above, temporal lobe lesions will cause a contralateral superior quadrantonopia.
These are "Meyer's loop" lesions.

| Hyphema | Retinal detachment |

Evaluation of gradual visual loss

[!INFO] Visual loss means loss of one or more of

• acuity
• Color vision
• visual field

Pearls

• Improvement of acuity with pin hole indicates uncorrected refractive error.
• Occular pathologies and prechiasmal optic neuropathies cause monocular vision loss.
• Amaurosis fugax also presents as transient monocular vision loss.
  • Consider AF as an omen of a stroke
• monocular vision loss is usually due to ocular or pre-chiasmal lesions.
  • Ocular pathologies (corneal, lenticular, vitreoretinal and macular) and prechiasmal optic neuropathies typically cause monocular vision loss.
• Binocular vision loss is usually due to retrochiasmal lesions.
  • In this case, assessment of visual fields can localize the lesions.
  • eg: temporal lobe Meyer's loop leions -> Superior homonymous quadrantonopia.
• most retinal causes of vision loss are painless
• Retrochiasmal lesions will cause contralateral homonymous visual field defects.

Central Vs. Peripheral vision loss:

• Poor central vision with peripheral sparing = macular involvement.
  • eg AMD
  • Manifests as distortions or paracentral scotoma.
• Constricted peripheral vision is usually caused by optic neuropathy.
  • eg: Chronic glaucoma
  • but there are also retinal causes of tunnel vision.
    • eg: retinitis pigmentosa

Speed of onset

• Vascular - rapid.
• Inflammatory - subacute (over days) (eg. optic neuritis, scleritis)
• Degenerative - gradual (cataract)

Leading causes of blindness

• Cataract
• Glaucoma
• Refractive error
• Age-related macular degeneration (AMD)
• Diabetic retinopathy

Retinal vessel occlusion

Source